Engine housing:

The engine housing (viewed from the bottom in the picture on the left) is the known version with the steel tube fixed in the housings light alloy on both sides.

Engine block with steel tube for the fixing bolt (top).
Housing with tube integrated in the light alloy casting (below)

This steel tube allows the lower engine mounting bolt to cross through the engine housing. Every restorer should inspect this tube carefully and disassemble the conical rubber bushings for that purpose.
These rubbers should be replaced, because they are becoming harder with the years and are then unable to cope with the engines vibrations.
I was searching for an oil leak at my first Bergmeister, changing the gaskets and sealings at the oil sump, cylinder and so on several times, just to find out that the steel tube of the engine mounting bolt was corroded though and let some oil pass. The oil found its way to the outside and leaked in direction oil sump. We don’t have to wonder about this “rust phenomenon”, because with the rubbers becoming hard, water can migrate from the outside though the bushings, doing its corrosive work in the steel tube.

Our IG-colleague Schinagl pointed out something special at his engine housing (see picture below), what we had not known till then. He was so kind to remove the oil sump once again to take that photo for us (Thanx!).

In this housing, there is no steel tube anymore, but the cross through engine mounting housing is now integrated into the block casting. These housing version is very rare, only to be found in the latest production series.

Unfortunately the engine number of this block was erased and changed to another one, so that there is no chance to find out when the plant changed the design here. It must have been with numbers higher than 4000. Reading the hint of the change in the tube design, IG-colleague and V35-owner Norbert Gräf sent us some photos (Thanx!) with the telling the number of his engine: 4135. Here he found the same design (see picture left).
This proves the conclusion that we will find this housing in the numbers above 4000.
The design of the oil supply of the rear camshaft bearing changed. According to the former casting technology it was impossible to cast the housing without that opening above the oil pressure contol plug (not shown in the parts catalog) on the right side of the engine. At the early engines, they  closed the hole below the right cylinder with a slotted head bolt. Later this was changed to closing by welding with aluminium. This can be recognized by the different structure in the aluminium of the housing.